1 files changed, 317 insertions, 158 deletions

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 2d966244ea6..fe75444ae7e 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -37,64 +37,129 @@
 static struct alarm_base {
 	spinlock_t		lock;
 	struct timerqueue_head	timerqueue;
-	struct hrtimer		timer;
 	ktime_t			(*gettime)(void);
 	clockid_t		base_clockid;
 } alarm_bases[ALARM_NUMTYPE];
 
+/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
+static ktime_t freezer_delta;
+static DEFINE_SPINLOCK(freezer_delta_lock);
+
+static struct wakeup_source *ws;
+
 #ifdef CONFIG_RTC_CLASS
 /* rtc timer and device for setting alarm wakeups at suspend */
 static struct rtc_timer		rtctimer;
 static struct rtc_device	*rtcdev;
-#endif
+static DEFINE_SPINLOCK(rtcdev_lock);
 
-/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
-static ktime_t freezer_delta;
-static DEFINE_SPINLOCK(freezer_delta_lock);
+/**
+ * alarmtimer_get_rtcdev - Return selected rtcdevice
+ *
+ * This function returns the rtc device to use for wakealarms.
+ * If one has not already been chosen, it checks to see if a
+ * functional rtc device is available.
+ */
+struct rtc_device *alarmtimer_get_rtcdev(void)
+{
+	unsigned long flags;
+	struct rtc_device *ret;
+
+	spin_lock_irqsave(&rtcdev_lock, flags);
+	ret = rtcdev;
+	spin_unlock_irqrestore(&rtcdev_lock, flags);
+
+	return ret;
+}
+
+
+static int alarmtimer_rtc_add_device(struct device *dev,
+				struct class_interface *class_intf)
+{
+	unsigned long flags;
+	struct rtc_device *rtc = to_rtc_device(dev);
+
+	if (rtcdev)
+		return -EBUSY;
 
+	if (!rtc->ops->set_alarm)
+		return -1;
+	if (!device_may_wakeup(rtc->dev.parent))
+		return -1;
+
+	spin_lock_irqsave(&rtcdev_lock, flags);
+	if (!rtcdev) {
+		rtcdev = rtc;
+		/* hold a reference so it doesn't go away */
+		get_device(dev);
+	}
+	spin_unlock_irqrestore(&rtcdev_lock, flags);
+	return 0;
+}
+
+static inline void alarmtimer_rtc_timer_init(void)
+{
+	rtc_timer_init(&rtctimer, NULL, NULL);
+}
+
+static struct class_interface alarmtimer_rtc_interface = {
+	.add_dev = &alarmtimer_rtc_add_device,
+};
+
+static int alarmtimer_rtc_interface_setup(void)
+{
+	alarmtimer_rtc_interface.class = rtc_class;
+	return class_interface_register(&alarmtimer_rtc_interface);
+}
+static void alarmtimer_rtc_interface_remove(void)
+{
+	class_interface_unregister(&alarmtimer_rtc_interface);
+}
+#else
+struct rtc_device *alarmtimer_get_rtcdev(void)
+{
+	return NULL;
+}
+#define rtcdev (NULL)
+static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
+static inline void alarmtimer_rtc_interface_remove(void) { }
+static inline void alarmtimer_rtc_timer_init(void) { }
+#endif
 
 /**
  * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
  * @base: pointer to the base where the timer is being run
  * @alarm: pointer to alarm being enqueued.
  *
- * Adds alarm to a alarm_base timerqueue and if necessary sets
- * an hrtimer to run.
+ * Adds alarm to a alarm_base timerqueue
  *
  * Must hold base->lock when calling.
  */
 static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
 {
+	if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
+		timerqueue_del(&base->timerqueue, &alarm->node);
+
 	timerqueue_add(&base->timerqueue, &alarm->node);
-	if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
-		hrtimer_try_to_cancel(&base->timer);
-		hrtimer_start(&base->timer, alarm->node.expires,
-				HRTIMER_MODE_ABS);
-	}
+	alarm->state |= ALARMTIMER_STATE_ENQUEUED;
 }
 
 /**
- * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
+ * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
  * @base: pointer to the base where the timer is running
  * @alarm: pointer to alarm being removed
  *
- * Removes alarm to a alarm_base timerqueue and if necessary sets
- * a new timer to run.
+ * Removes alarm to a alarm_base timerqueue
  *
  * Must hold base->lock when calling.
  */
-static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
+static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
 {
-	struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
+	if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
+		return;
 
 	timerqueue_del(&base->timerqueue, &alarm->node);
-	if (next == &alarm->node) {
-		hrtimer_try_to_cancel(&base->timer);
-		next = timerqueue_getnext(&base->timerqueue);
-		if (!next)
-			return;
-		hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
-	}
+	alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
 }
 
 
@@ -109,39 +174,23 @@ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
  */
 static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 {
-	struct alarm_base *base = container_of(timer, struct alarm_base, timer);
-	struct timerqueue_node *next;
+	struct alarm *alarm = container_of(timer, struct alarm, timer);
+	struct alarm_base *base = &alarm_bases[alarm->type];
 	unsigned long flags;
-	ktime_t now;
 	int ret = HRTIMER_NORESTART;
+	int restart = ALARMTIMER_NORESTART;
 
 	spin_lock_irqsave(&base->lock, flags);
-	now = base->gettime();
-	while ((next = timerqueue_getnext(&base->timerqueue))) {
-		struct alarm *alarm;
-		ktime_t expired = next->expires;
-
-		if (expired.tv64 >= now.tv64)
-			break;
-
-		alarm = container_of(next, struct alarm, node);
+	alarmtimer_dequeue(base, alarm);
+	spin_unlock_irqrestore(&base->lock, flags);
 
-		timerqueue_del(&base->timerqueue, &alarm->node);
-		alarm->enabled = 0;
-		/* Re-add periodic timers */
-		if (alarm->period.tv64) {
-			alarm->node.expires = ktime_add(expired, alarm->period);
-			timerqueue_add(&base->timerqueue, &alarm->node);
-			alarm->enabled = 1;
-		}
-		spin_unlock_irqrestore(&base->lock, flags);
-		if (alarm->function)
-			alarm->function(alarm);
-		spin_lock_irqsave(&base->lock, flags);
-	}
+	if (alarm->function)
+		restart = alarm->function(alarm, base->gettime());
 
-	if (next) {
-		hrtimer_set_expires(&base->timer, next->expires);
+	spin_lock_irqsave(&base->lock, flags);
+	if (restart != ALARMTIMER_NORESTART) {
+		hrtimer_set_expires(&alarm->timer, alarm->node.expires);
+		alarmtimer_enqueue(base, alarm);
 		ret = HRTIMER_RESTART;
 	}
 	spin_unlock_irqrestore(&base->lock, flags);
@@ -150,6 +199,13 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 
 }
 
+ktime_t alarm_expires_remaining(const struct alarm *alarm)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+	return ktime_sub(alarm->node.expires, base->gettime());
+}
+EXPORT_SYMBOL_GPL(alarm_expires_remaining);
+
 #ifdef CONFIG_RTC_CLASS
 /**
  * alarmtimer_suspend - Suspend time callback
@@ -166,15 +222,18 @@ static int alarmtimer_suspend(struct device *dev)
 	struct rtc_time tm;
 	ktime_t min, now;
 	unsigned long flags;
+	struct rtc_device *rtc;
 	int i;
+	int ret;
 
 	spin_lock_irqsave(&freezer_delta_lock, flags);
 	min = freezer_delta;
 	freezer_delta = ktime_set(0, 0);
 	spin_unlock_irqrestore(&freezer_delta_lock, flags);
 
+	rtc = alarmtimer_get_rtcdev();
 	/* If we have no rtcdev, just return */
-	if (!rtcdev)
+	if (!rtc)
 		return 0;
 
 	/* Find the soonest timer to expire*/
@@ -195,18 +254,22 @@ static int alarmtimer_suspend(struct device *dev)
 	if (min.tv64 == 0)
 		return 0;
 
-	/* XXX - Should we enforce a minimum sleep time? */
-	WARN_ON(min.tv64 < NSEC_PER_SEC);
+	if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
+		__pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
+		return -EBUSY;
+	}
 
 	/* Setup an rtc timer to fire that far in the future */
-	rtc_timer_cancel(rtcdev, &rtctimer);
-	rtc_read_time(rtcdev, &tm);
+	rtc_timer_cancel(rtc, &rtctimer);
+	rtc_read_time(rtc, &tm);
 	now = rtc_tm_to_ktime(tm);
 	now = ktime_add(now, min);
 
-	rtc_timer_start(rtcdev, &rtctimer, now, ktime_set(0, 0));
-
-	return 0;
+	/* Set alarm, if in the past reject suspend briefly to handle */
+	ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
+	if (ret < 0)
+		__pm_wakeup_event(ws, MSEC_PER_SEC);
+	return ret;
 }
 #else
 static int alarmtimer_suspend(struct device *dev)
@@ -237,51 +300,146 @@ static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
  * @function: callback that is run when the alarm fires
  */
 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
-		void (*function)(struct alarm *))
+		enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
 {
 	timerqueue_init(&alarm->node);
-	alarm->period = ktime_set(0, 0);
+	hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
+			HRTIMER_MODE_ABS);
+	alarm->timer.function = alarmtimer_fired;
 	alarm->function = function;
 	alarm->type = type;
-	alarm->enabled = 0;
+	alarm->state = ALARMTIMER_STATE_INACTIVE;
 }
+EXPORT_SYMBOL_GPL(alarm_init);
 
 /**
- * alarm_start - Sets an alarm to fire
+ * alarm_start - Sets an absolute alarm to fire
  * @alarm: ptr to alarm to set
  * @start: time to run the alarm
- * @period: period at which the alarm will recur
  */
-void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period)
+int alarm_start(struct alarm *alarm, ktime_t start)
 {
 	struct alarm_base *base = &alarm_bases[alarm->type];
 	unsigned long flags;
+	int ret;
 
 	spin_lock_irqsave(&base->lock, flags);
-	if (alarm->enabled)
-		alarmtimer_remove(base, alarm);
 	alarm->node.expires = start;
-	alarm->period = period;
 	alarmtimer_enqueue(base, alarm);
-	alarm->enabled = 1;
+	ret = hrtimer_start(&alarm->timer, alarm->node.expires,
+				HRTIMER_MODE_ABS);
+	spin_unlock_irqrestore(&base->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(alarm_start);
+
+/**
+ * alarm_start_relative - Sets a relative alarm to fire
+ * @alarm: ptr to alarm to set
+ * @start: time relative to now to run the alarm
+ */
+int alarm_start_relative(struct alarm *alarm, ktime_t start)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+
+	start = ktime_add(start, base->gettime());
+	return alarm_start(alarm, start);
+}
+EXPORT_SYMBOL_GPL(alarm_start_relative);
+
+void alarm_restart(struct alarm *alarm)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+	unsigned long flags;
+
+	spin_lock_irqsave(&base->lock, flags);
+	hrtimer_set_expires(&alarm->timer, alarm->node.expires);
+	hrtimer_restart(&alarm->timer);
+	alarmtimer_enqueue(base, alarm);
 	spin_unlock_irqrestore(&base->lock, flags);
 }
+EXPORT_SYMBOL_GPL(alarm_restart);
 
 /**
- * alarm_cancel - Tries to cancel an alarm timer
+ * alarm_try_to_cancel - Tries to cancel an alarm timer
  * @alarm: ptr to alarm to be canceled
+ *
+ * Returns 1 if the timer was canceled, 0 if it was not running,
+ * and -1 if the callback was running
  */
-void alarm_cancel(struct alarm *alarm)
+int alarm_try_to_cancel(struct alarm *alarm)
 {
 	struct alarm_base *base = &alarm_bases[alarm->type];
 	unsigned long flags;
+	int ret;
 
 	spin_lock_irqsave(&base->lock, flags);
-	if (alarm->enabled)
-		alarmtimer_remove(base, alarm);
-	alarm->enabled = 0;
+	ret = hrtimer_try_to_cancel(&alarm->timer);
+	if (ret >= 0)
+		alarmtimer_dequeue(base, alarm);
 	spin_unlock_irqrestore(&base->lock, flags);
+	return ret;
 }
+EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
+
+
+/**
+ * alarm_cancel - Spins trying to cancel an alarm timer until it is done
+ * @alarm: ptr to alarm to be canceled
+ *
+ * Returns 1 if the timer was canceled, 0 if it was not active.
+ */
+int alarm_cancel(struct alarm *alarm)
+{
+	for (;;) {
+		int ret = alarm_try_to_cancel(alarm);
+		if (ret >= 0)
+			return ret;
+		cpu_relax();
+	}
+}
+EXPORT_SYMBOL_GPL(alarm_cancel);
+
+
+u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
+{
+	u64 overrun = 1;
+	ktime_t delta;
+
+	delta = ktime_sub(now, alarm->node.expires);
+
+	if (delta.tv64 < 0)
+		return 0;
+
+	if (unlikely(delta.tv64 >= interval.tv64)) {
+		s64 incr = ktime_to_ns(interval);
+
+		overrun = ktime_divns(delta, incr);
+
+		alarm->node.expires = ktime_add_ns(alarm->node.expires,
+							incr*overrun);
+
+		if (alarm->node.expires.tv64 > now.tv64)
+			return overrun;
+		/*
+		 * This (and the ktime_add() below) is the
+		 * correction for exact:
+		 */
+		overrun++;
+	}
+
+	alarm->node.expires = ktime_add(alarm->node.expires, interval);
+	return overrun;
+}
+EXPORT_SYMBOL_GPL(alarm_forward);
+
+u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+
+	return alarm_forward(alarm, base->gettime(), interval);
+}
+EXPORT_SYMBOL_GPL(alarm_forward_now);
 
 
 /**
@@ -303,12 +461,21 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid)
  *
  * Posix timer callback for expired alarm timers.
  */
-static void alarm_handle_timer(struct alarm *alarm)
+static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
+							ktime_t now)
 {
 	struct k_itimer *ptr = container_of(alarm, struct k_itimer,
-						it.alarmtimer);
+						it.alarm.alarmtimer);
 	if (posix_timer_event(ptr, 0) != 0)
 		ptr->it_overrun++;
+
+	/* Re-add periodic timers */
+	if (ptr->it.alarm.interval.tv64) {
+		ptr->it_overrun += alarm_forward(alarm, now,
+						ptr->it.alarm.interval);
+		return ALARMTIMER_RESTART;
+	}
+	return ALARMTIMER_NORESTART;
 }
 
 /**
@@ -322,6 +489,9 @@ static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
 {
 	clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
 
+	if (!alarmtimer_get_rtcdev())
+		return -EINVAL;
+
 	return hrtimer_get_res(baseid, tp);
 }
 
@@ -336,6 +506,9 @@ static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
 {
 	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
 
+	if (!alarmtimer_get_rtcdev())
+		return -EINVAL;
+
 	*tp = ktime_to_timespec(base->gettime());
 	return 0;
 }
@@ -351,12 +524,15 @@ static int alarm_timer_create(struct k_itimer *new_timer)
 	enum  alarmtimer_type type;
 	struct alarm_base *base;
 
+	if (!alarmtimer_get_rtcdev())
+		return -ENOTSUPP;
+
 	if (!capable(CAP_WAKE_ALARM))
 		return -EPERM;
 
 	type = clock2alarm(new_timer->it_clock);
 	base = &alarm_bases[type];
-	alarm_init(&new_timer->it.alarmtimer, type, alarm_handle_timer);
+	alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
 	return 0;
 }
 
@@ -370,10 +546,12 @@ static int alarm_timer_create(struct k_itimer *new_timer)
 static void alarm_timer_get(struct k_itimer *timr,
 				struct itimerspec *cur_setting)
 {
+	memset(cur_setting, 0, sizeof(struct itimerspec));
+
 	cur_setting->it_interval =
-			ktime_to_timespec(timr->it.alarmtimer.period);
+			ktime_to_timespec(timr->it.alarm.interval);
 	cur_setting->it_value =
-			ktime_to_timespec(timr->it.alarmtimer.node.expires);
+		ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
 	return;
 }
 
@@ -385,7 +563,12 @@ static void alarm_timer_get(struct k_itimer *timr,
  */
 static int alarm_timer_del(struct k_itimer *timr)
 {
-	alarm_cancel(&timr->it.alarmtimer);
+	if (!rtcdev)
+		return -ENOTSUPP;
+
+	if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
+		return TIMER_RETRY;
+
 	return 0;
 }
 
@@ -402,19 +585,33 @@ static int alarm_timer_set(struct k_itimer *timr, int flags,
 				struct itimerspec *new_setting,
 				struct itimerspec *old_setting)
 {
-	/* Save old values */
-	old_setting->it_interval =
-			ktime_to_timespec(timr->it.alarmtimer.period);
-	old_setting->it_value =
-			ktime_to_timespec(timr->it.alarmtimer.node.expires);
+	ktime_t exp;
+
+	if (!rtcdev)
+		return -ENOTSUPP;
+
+	if (flags & ~TIMER_ABSTIME)
+		return -EINVAL;
+
+	if (old_setting)
+		alarm_timer_get(timr, old_setting);
 
 	/* If the timer was already set, cancel it */
-	alarm_cancel(&timr->it.alarmtimer);
+	if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
+		return TIMER_RETRY;
 
 	/* start the timer */
-	alarm_start(&timr->it.alarmtimer,
-			timespec_to_ktime(new_setting->it_value),
-			timespec_to_ktime(new_setting->it_interval));
+	timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
+	exp = timespec_to_ktime(new_setting->it_value);
+	/* Convert (if necessary) to absolute time */
+	if (flags != TIMER_ABSTIME) {
+		ktime_t now;
+
+		now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
+		exp = ktime_add(now, exp);
+	}
+
+	alarm_start(&timr->it.alarm.alarmtimer, exp);
 	return 0;
 }
 
@@ -424,13 +621,15 @@ static int alarm_timer_set(struct k_itimer *timr, int flags,
  *
  * Wakes up the task that set the alarmtimer
  */
-static void alarmtimer_nsleep_wakeup(struct alarm *alarm)
+static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
+								ktime_t now)
 {
 	struct task_struct *task = (struct task_struct *)alarm->data;
 
 	alarm->data = NULL;
 	if (task)
 		wake_up_process(task);
+	return ALARMTIMER_NORESTART;
 }
 
 /**
@@ -445,7 +644,7 @@ static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
 	alarm->data = (void *)current;
 	do {
 		set_current_state(TASK_INTERRUPTIBLE);
-		alarm_start(alarm, absexp, ktime_set(0, 0));
+		alarm_start(alarm, absexp);
 		if (likely(alarm->data))
 			schedule();
 
@@ -541,6 +740,12 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 	int ret = 0;
 	struct restart_block *restart;
 
+	if (!alarmtimer_get_rtcdev())
+		return -ENOTSUPP;
+
+	if (flags & ~TIMER_ABSTIME)
+		return -EINVAL;
+
 	if (!capable(CAP_WAKE_ALARM))
 		return -EPERM;
 
@@ -603,6 +808,7 @@ static struct platform_driver alarmtimer_driver = {
  */
 static int __init alarmtimer_init(void)
 {
+	struct platform_device *pdev;
 	int error = 0;
 	int i;
 	struct k_clock alarm_clock = {
@@ -615,6 +821,8 @@ static int __init alarmtimer_init(void)
 		.nsleep		= alarm_timer_nsleep,
 	};
 
+	alarmtimer_rtc_timer_init();
+
 	posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
 	posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
 
@@ -626,77 +834,28 @@ static int __init alarmtimer_init(void)
 	for (i = 0; i < ALARM_NUMTYPE; i++) {
 		timerqueue_init_head(&alarm_bases[i].timerqueue);
 		spin_lock_init(&alarm_bases[i].lock);
-		hrtimer_init(&alarm_bases[i].timer,
-				alarm_bases[i].base_clockid,
-				HRTIMER_MODE_ABS);
-		alarm_bases[i].timer.function = alarmtimer_fired;
 	}
-	error = platform_driver_register(&alarmtimer_driver);
-	platform_device_register_simple("alarmtimer", -1, NULL, 0);
-
-	return error;
-}
-device_initcall(alarmtimer_init);
-
-#ifdef CONFIG_RTC_CLASS
-/**
- * has_wakealarm - check rtc device has wakealarm ability
- * @dev: current device
- * @name_ptr: name to be returned
- *
- * This helper function checks to see if the rtc device can wake
- * from suspend.
- */
-static int __init has_wakealarm(struct device *dev, void *name_ptr)
-{
-	struct rtc_device *candidate = to_rtc_device(dev);
-
-	if (!candidate->ops->set_alarm)
-		return 0;
-	if (!device_may_wakeup(candidate->dev.parent))
-		return 0;
 
-	*(const char **)name_ptr = dev_name(dev);
-	return 1;
-}
+	error = alarmtimer_rtc_interface_setup();
+	if (error)
+		return error;
 
-/**
- * alarmtimer_init_late - Late initializing of alarmtimer code
- *
- * This function locates a rtc device to use for wakealarms.
- * Run as late_initcall to make sure rtc devices have been
- * registered.
- */
-static int __init alarmtimer_init_late(void)
-{
-	struct device *dev;
-	char *str;
+	error = platform_driver_register(&alarmtimer_driver);
+	if (error)
+		goto out_if;
 
-	/* Find an rtc device and init the rtc_timer */
-	dev = class_find_device(rtc_class, NULL, &str, has_wakealarm);
-	/* If we have a device then str is valid. See has_wakealarm() */
-	if (dev) {
-		rtcdev = rtc_class_open(str);
-		/*
-		 * Drop the reference we got in class_find_device,
-		 * rtc_open takes its own.
-		 */
-		put_device(dev);
-	}
-	if (!rtcdev) {
-		printk(KERN_WARNING "No RTC device found, ALARM timers will"
-			" not wake from suspend");
+	pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		error = PTR_ERR(pdev);
+		goto out_drv;
 	}
-	rtc_timer_init(&rtctimer, NULL, NULL);
-
-	return 0;
-}
-#else
-static int __init alarmtimer_init_late(void)
-{
-	printk(KERN_WARNING "Kernel not built with RTC support, ALARM timers"
-		" will not wake from suspend");
+	ws = wakeup_source_register("alarmtimer");
 	return 0;
+
+out_drv:
+	platform_driver_unregister(&alarmtimer_driver);
+out_if:
+	alarmtimer_rtc_interface_remove();
+	return error;
 }
-#endif
-late_initcall(alarmtimer_init_late);
+device_initcall(alarmtimer_init);